Chromium (III) hydroxide

General
Surname	Chromium (III) hydroxide
other names	Chromium hydroxide
Molecular formula	Cr (OH) 3
Brief description	as a hydrate, green to blue powder or black particles
External identifiers / databases
EC number	215-158-8
ECHA InfoCard	100,013,781
PubChem	14787
ChemSpider	145861
Wikidata	Q410563
properties
Molar mass	103.02 g mol −1
Physical state	firmly
solubility	poorly soluble in water
safety instructions
GHS labeling of hazardous substances	no GHS pictograms
	no GHS pictograms
H and P phrases	H: no H-phrases
	P: no P-phrases
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Chromium (III) hydroxide is a chemical compound from the group of hydroxides with the formula Cr (OH) ₃ .

Extraction and presentation

Precipitation of chromium (III) hydroxide from a chromium (III) sulfate solution

Chromium (III) hydroxide can be produced by precipitation from chromium (III) chloride or chromium (III) sulfate solution with ammonia. It forms a gray to green precipitate.

{\ displaystyle \ mathrm {Cr ^ {3 +} + 3 \ OH ^ {-} \ longrightarrow Cr (OH) _ {3}}}

Larger quantities are accessible in the laboratory by converting chromium (VI) oxide with ethanol and then refluxing:

{\ displaystyle {\ ce {2 CrO3 + 3 C2H5OH -> 2 Cr (OH) 3 + 3 CH3CHO + 3 H2O}}}

properties

Chromium (III) hydroxide (like many metal hydroxides) is sparingly soluble in water. It is an amphoteric hydroxide, so it is soluble in both acidic and alkaline media. In acids it dissolves with the formation of Cr ³⁺ ions, in concentrated bases with the formation of green [Cr (OH) ₆ ] ³⁻ ions.

use

Chromium (III) hydroxide is used to produce chromium - pigments used.

Individual evidence

↑ Chromic (III) hydroxide hydrate ICSC (ILO)
↑ ^a ^b ^c Entry on chromium (III) hydroxide in the GESTIS substance database of the IFA , accessed on February 28, 2017(JavaScript required) .
↑ Jander-Blasius: Textbook of analytical and preparative inorganic chemistry , 5th edition, S. Hirzel, Stuttgart 1965, p. 225
↑ Georg Brauer: Chromium (III) hydroxide . In: Handbook of Preparative Inorganic Chemistry . Ferdinand Enke Verlag, Stuttgart 1954, p. 1008-1009 .

[1] Chromic (III) hydroxide hydrate ICSC (ILO)

[GESTIS-2] Entry on chromium (III) hydroxide in the GESTIS substance database of the IFA , accessed on February 28, 2017(JavaScript required) .

[3] Jander-Blasius: Textbook of analytical and preparative inorganic chemistry , 5th edition, S. Hirzel, Stuttgart 1965, p. 225

[Brauer-4] Georg Brauer: Chromium (III) hydroxide . In: Handbook of Preparative Inorganic Chemistry . Ferdinand Enke Verlag, Stuttgart 1954, p. 1008-1009 .